So it looks like the Z80 and both Z8002's initialize and pass all memory checks and the Z80 is at the point in the code where it is looking for some status from the 06xx. Now the 06xx is basically a customs controller and it has the ability to control up to 4 separate Namco 5XXX series devices. As it stands.. Pole Position actually has 4 of these: 51xx, 52xx, 53xx and a 54xx
So this means I have to now reverse engineer 5 more Namco customs. Or do I?
Calling in a favor from my buddy Wolfgang, who has been working in parallel on an FPGA implementation of the Galaga system. He and I have been sharing the code for our customs for a while and I'm happy to see that he has already done quite a bit of this work: